Few would argue that jazz virtuosity and a flair for spontaneous improvisation are two sides of the same coin. Still, a surprising number of accomplished players rely on the ingenious stringing together and reshuffling of tried and tested riffs and melodies. Not so Janette Mason, the UK-based pianist who has lent her talents to artists as diverse as Pulp and Robert Wyatt, and who is now stepping out as a band leader of pugnacious flair and genuine unpredictability.

Mason has only managed to recruit two of the nine musicians (bassist Dudley Phillips and drummer Simon Pearson) who played on her debut album Din and Tonic. The record's chief saxophonist, Mornington Lockett, is replaced by Julian Siegel, whose less lyrical approach finds counterbalance in his melodic resourcefulness and his propensity for virile swing and funk.

Presaged with a cheeky-sounding four-note melody, Urban Chant sets out Mason's wares as both composer and soloist. With its sun-dappled spaces, it is redolent of African township music, but Mason's quicksilver right hand and volcanic chordal accompaniment complicate matters delightfully. On this and other up-tempo tunes her conception is a spirited mix of McCoy Tyner's fervency and Herbie Hancock's flights of fancy, all delivered with gumption.

A wobbly organ chord ushers in a brand new piece called The Blues Walked Out, which soon teeters under the weight of a heavy piano ostinato and some obstreperous snare rolls from Pearson. It all then reaches an unexpectedly cool plateau, with wry Sonny Rollins-like playing by Siegel above a greasy swing rhythm. As with many of Mason's compositions, a crescendo isn't far away, and the tune climaxes as a bar-room stomp with lashings of sustain pedal. Mason's music is a brow-beating and monolithic at times, but it pulls no punches.